Sorters have evolved for use with office copiers and printers for sorting sheets into collated sets or separating sets of sheets or jobs and the sets are stapled together in the sorter trays. An example is shown in my U.S. patent application Ser. No. 848,489, filed Mar. 9, 1992, co-owned herewith.
The trays may also be shifted to a stapler, for example, as shown in Kramer et al U.S. Pat. No. 4,925,171; the sets may be partially removed from the trays, stapled and returned to the trays as disclosed in Lawrence U.S. application Ser. No. 730,746, filed Jul. 16, 1991, co-owned herewith, or the sets may be transferred to a stapler as in Crammer U.S. Pat. No. 4,361,373.
In all of these devices the stapling function creates an objectionable noise. Moreover, the stapler, in use is adapted to drive a staple into a set of sheets of some maximum number of sheets or thickness, depending upon the capacity of the sorter and the copier or printer with which the sorter is employed and the stapler construction.
As a result, the force applied to cause the movement of the stapler hammer or driver towards the stapler anvil and the resultant noise caused by the inserting and clinching of the staple is at the same high level, regardless of the number of sheets actually in the set of sheets to which the staple is being applied. When such stapling noise is repeated, numerous times, as staples are applied to, say, twenty sets, at a number of, say, three locations, the distraction of workers by the driving of sixty staples may be serious.
Just as importantly, the noise may exceed the permissible office noise under some regulations controlling office environment.
It is also known, as disclosed in Ishigino et al U.S. Pat. No. 4,864,350, Sep. 5, 1989, for example, that sheets entering a sorter may be counted, whereby the stapler may be disabled if the count is outside of a range of sheets, say, a range between 1 and 25, so that single sheets or sets of sheets exceeding the capacity of the stapler can not be stapled.